public function build()
{
$ret = 'REPLACE ' . $this->options . ' INTO ' . $this->into;
if ($this->values != NULL && count($this->values) > 0) {
$ret .= ' VALUES ' . Array2d::build($this->values);
} elseif ($this->set != NULL && count($this->set) > 0) {
$ret .= ' SET ' . SetOperation::build($this->set);
} elseif ($this->select != NULL && strlen($this->select) > 0) {
$ret .= ' ' . $this->select->build();
}
return $ret;
}